ES2428272T3 - Removal of organic dyes and organic pollutants using titanium peroxide gel - Google Patents

Abstract

A one-step process for the removal of organic dye and / or organic pollutants from dissolution using titanium peroxide gel, said process comprising: a) adding titanium peroxide gel to the solution in a ratio ranging from 1: 5 to 1 : 20 volume / volume degel / dye solution; b) stir the mixture as obtained in step (a) vigorously at a temperature ranging from 25-35 ° C; c) allow the mixture to stand as obtained in step (b) for 5 to 25 minutes to obtain organic dye or organic pollutant adsorbed on titanium peroxide gel and colorless supernatant, of course, followed by filtration of the mixture to obtain adsorbed organic dye or contaminant in titanium peroxide gel; d) transfer organic dye or contaminant adsorbed on titanium peroxide gel as obtained in step (c) in a beaker containing water; e) Degrade dye or organic contaminant adsorbed from the dye or organic contaminant adsorbed on titanium peroxide gel to recover the titanium peroxide gel for reuse.

Description

Elimination of organic dyes and organic pollutants by means of titanium peroxide gel.

Field of the Invention

The present invention relates to a process for the removal of organic dye and organic solution contaminants using titanium peroxide gel. The present invention also relates to a process for the regeneration of titanium peroxide gel that can be reused by the removal process.

Background and prior art

The textile and dye industries are considered to be two of the most polluting industries. While the concentration of colored components or components that contribute to the color in the effluent may be very small and may not always be toxic, they are a cause for substantial public apprehension due to the intense and unacceptable color of the effluents. Physical, chemical, biological and physicochemical methods have been tested to treat these chromophores with various advantages and disadvantages. It seems that now the proposal has changed from its treatment to its elimination. The factors that have to be considered regarding the disposal by physical, chemical, biological and physicochemical methods include cost, efficiency, color, need for large areas of space, ease of use, generation of concentrated sludge, large amount of dissolved solids posing problems for recirculation or safe disposal in the environment among others.

The investigation of new photocatalysts using semiconductor materials (eg, titanium dioxide) has consequently led to scientific and commercial purposes. In particular, titanium dioxide photocatalysts have been used as a means to remove contaminants that cause significant environmental problems.

An article entitled "Sol-gel synthesis of Au / TiO2 thin films for photo catalytic degradation of phenol in sunlight" in the Journal of Molecular Catalysis A: Chemical 243 (2006) 68-76 by RS Sonawana, MK Dongare reveals the preparation of thin films of Au / TiO2 used in photocatalytic decomposition of organic matter and capable of being reused repeatedly.

The photocatalytic degradation of various types of dyes such as Alizarin S, Crocein Orange G, Methyl Red, Congo Red, Methylene Blue and other organic pollutants in water by UV irradiated titania, is disclosed in the article entitled "Photocatalytic degradation of various types of dyes in water by UV-irradiated titania "by Hinda Lachheb, Eric Puzenat, Ammar Houas in Applied Catalysis B: Environmental Volume 39, Issue 1, November 8, 2002, Pages 75-90.

The article entitled "Tailored titanium dioxide photocatalysts for the degradation of organic dyes in wastewater treatment." A review by Fang Han, Venkata Subba et al in applied Catalysis A: General Volume 359, Issues 1-2, May 15, 2009, Pages 25-40; discloses the photocatalytic decomposition of organic pollutants and organic dyes from industrial wastewater effluents involving modified TiO2 or TiO2.

The article entitled "Preparation of titanium (IV) oxide thin film photo catalyst by sol-gel dip coating" in Materials Chemistry and Physics 77 (2003) 744-750 by RS Sonawane, SG Hegde, MK Dongare, unveils TiO2 films that are used for photocatalytic decomposition of salicylic acid and methylene blue.

The article in the International Journal of Photoenergy Volume 2.009, Article ID 962783, 8 pages doi: 10.1155 / 2009/962783 entitled "Nanosized TiO2 photocatalyst powder via sol-gel method: effect of hydrolysis degree on powder properties" by Nor Hafizah and Iis Sopyan reveals the synthesis of nanodimensional TiO2 powder by the sol-gel method using titanium tetraisopropoxide (TPT) as the precursor in methanol for degradation of phenol and other organic pollutants.

An article entitled "Photocatalytic degradation of an azo dye in a tubular continuous-flow photoreactor with immobilized TiO2 on glass plates" by Behnajady M. A. et al in Chemical engineering journal ISSN 1.385-8.947, 2.007, vol. 127, nol-3, p. 167-176 discloses the photocatalytic degradation of Acid Red C. I. 27 (AR27), an anionic acid-class monoazoic dye in aqueous solutions in a tubular continuous flow photoreactor with TiO2 immobilized on glass plates. It was observed that the elimination efficiency increases as the intensity of the light increases but decreases when the flow rate increases. The final output current of the photoreactor showed complete mineralization of the dye.

A disadvantage associated with the use of titanium dioxide as a photocatalyst is that light of short wavelengths in the ultraviolet (UV) region is required. Also, TiO2 absorbs only 3-5% of energy from the solar spectrum. For these reasons, there is a continuing need to modify pure titanium dioxide to develop photocatalytic materials capable of possessing photocatalytic activity even under visible light.

In addition, the molecular modification achieved in the prior art processes is complex and depends on the concentration of monomer, proportion of bimolecular condensation and functionality that depends

of the proportion of hydrolysis. On the other hand, TiO2 is used as thin or polymeric gel powder films. The photocatalytic activity is observed to be low due to low porosity and low area.

Also, TiO2 films for photocatalytic decomposition of organic matter experience disadvantages of efficiency and versatility. The thin film comprises 100% TiO2, where as the gel of the invention has been prepared with Ti salt in extremely low concentration. In addition, the Ti film is limited in its ability to treat a variety of dyes as against the gel of the invention as exemplified herein.

Therefore, there is still a need in the art to provide a simple procedure for chromophores removal.

Also, the procedure should be such that the treated effluent appears colorless after chromophore removal. Preferably, the sludge generated from the procedure should be easily degradable without additional processing procedures that require time and energy resources. In addition, it would be definitely advantageous if the method of the invention for removing chromophores simultaneously removes other contaminants such as phenol, methanol, formalin, hexamine and the like from effluents, since their removal is also an interesting task to satisfy environmental regulations.

Objectives of the invention

The main object of the invention is to develop a process for the removal of organic dye and organic solution contaminants using titanium peroxide gel.

The other object of the invention is to develop an economical, efficient process for the separation of organic dyes and organic pollutants using polymer without a modified titanium peroxide gel.

Another object of the present invention is to provide a process according to which the titanium peroxide gel used for the separation of environmental contaminants can be regenerated and reused.

Summary of the invention

Accordingly, the present invention provides a process for the removal of organic dye and organic solution contaminants using titanium peroxide gel, wherein the solution of organic chromophores, dyes or contaminants is mixed with titanium peroxide gel a room temperature and allowed to stand for a period of 5 to 25 minutes to obtain an almost colorless, clear solution.

In one aspect, the Titanium Peroxide Gel with high viscosity and high zeta potential is optionally doped with metals or metal oxides. The titanium peroxide gel of the present invention is polymer free. The titanium salt in the gel is in the range of 0.001-0.005% by weight. The metals are doped in the range of 0.1-4% by weight and the particle size of the doped metals is less than 10 nm.

In another aspect, titanium peroxide gel can be recovered by degradation of chromophore / dye / organic pollutants by procedures selected from, but not limited to, exposure to natural or artificial source light, physical treatment, chemical treatment, treatment with oxidizing agents. as commercial hypochlorites or bleaching agents and the like.

In another aspect of the process of the present invention, the gel is placed on a column and the dye solution is passed through it to collect clear solution downstream.

In one embodiment of the present invention, a one-step process for the removal of organic dye and / or organic solution contaminants using titanium peroxide gel, said process comprising:

a) add titanium peroxide gel to the solution in a ratio ranging from 1: 5 to 1:20 volume / volume of gel / dye solution;

b) stir the mixture as obtained in step (a) vigorously at a temperature ranging from 25-35 ° C;

c) Let the mixture stand as obtained in step (b) for 5 to 25 minutes to obtain an organic dye or contaminant adsorbed on a titanium peroxide gel and a colorless supernatant, followed by filtration of the mixture to obtain an organic dye or contaminant. adsorbed on titanium peroxide gel;

d) transfer organic dye or contaminant adsorbed on titanium peroxide gel as obtained in the step

(c) in a beaker containing water;

e) degrade dye or organic pollutant adsorbed from the dye or organic pollutant adsorbed on titanium peroxide gel to recover the titanium peroxide gel that can be recycled and reused.

In another embodiment of the present invention, wherein the solution comprises organic dye and / or organic contaminants and a solvent selected from the group consisting of: water, acetone, chlorinated solvents and alcohols.

In another embodiment of the present invention, wherein the titanium peroxide gel used in step (a) has a zeta potential in the range of -54 to -25 mV and viscosity in the range of 12-15 Pa.s (12,000 -15,000 cps).

In another embodiment of the present invention, wherein the titanium peroxide gel used in step (a) is optionally doped with noble and transition metals selected from the group consisting of Au, Ag, nickel, copper, iron, molybdenum , vanadium, tungsten and platinum in the range of 0.1-4% by weight.

In another embodiment of the present invention, in which an organic dye or an organic contaminant used is selected from the group of: methylene blue, methyl orange, methyl violet, malachite green, Rhodamine B, bromophenol blue, parabase solution , magenta solution, ink, formaldehyde solution, synthetic hexamine wastewater, phenol.

In another embodiment of the present invention, in which the titanium peroxide gel used in step (a) is optionally placed on a column and the dye solution is allowed to pass through it to obtain clear, colorless supernatant.

In another embodiment of the present invention, in which the concentration of the organic dye and organic contaminants is removed up to 95-100%.

In another embodiment of the present invention, wherein said degradation of organic dye and organic pollutant of organic dye or contaminant adsorbed on titanium peroxide gel in step (f) is done by exposure to sunlight with or without an oxidant.

In another embodiment of the present invention, wherein the oxidant used is selected from the group consisting of hydrogen peroxide and sodium hypochlorite.

Detailed description of the invention

"Titanium peroxide gel" of the invention is defined for the purpose of this document as "The solution of titanium salts which after condensation / polymerization forms a viscous jelly like structure with higher zeta potential."

"Organic dye" of the invention includes the component that contributes to its color, the chromophores.

The present invention relates to a process in which optionally modified / doped titanium peroxide gels with high viscosity and high zeta potential are used for the removal of chromophore / dye / organic contaminants from industrial aqueous effluents by adsorption on these gels. The gel that is not soluble in aqueous solution can be recovered and can be reused several times.

The present invention relates to a process in a container for removal of chromophore / dye / organic pollutant in steps comprising:

a) optionally mixing doped, polymer-free titanium peroxide gel with the organic chromophore / dye / contaminant solution and let the mixture stand for 5 to 25 minutes according to which the organic chromophore / dye / contaminant is adsorbed on the gel ;

b) separating the gel-chromophore, gel-dye or gel-contaminant, adsorbed, to obtain colorless, clear and supernatant

c) Degrade the gel-chromophore, gel-dye or gel-contaminant, separated, to recover the gel that can be recycled and reused.

Alternatively, the process for separating organic dye or contaminant comprises eluting the organic chromophore / dye / contaminant solution by a glass column that optionally consists of doped polymer-free titanium peroxide gel at a rate of 5 ml / min. to obtain a colorless, clear solution. The titanium peroxide gel used in the process can be recovered by degradation of the organic chromophore / dye / contaminant.

Step (a) and step (b) of the process of the present invention comprise mixing an organic chromophore / dye / contaminant solution and optionally doped titanium peroxide gel with vigorous stirring and let stand for 5 to 25 minutes; according to which the chromophore / dye / organic contaminant is adsorbed on the gel. In sedimentation, the adsorbed organic gel-chromophore / colorant / contaminant is separated to obtain clear, colorless supernatant. Contaminant content in the supernatant is measured by measuring its optical absorption at 665.612.290 and wavelength of 245 nm using UV-VIS spectrophotometer.

The gel-chromophore / dye / organic pollutant is separated from the solution treated by procedures

Selected filtration, decantation and the like.

The concentration of the chromophore in the solution is 10-3 to 10-6 molar, which becomes almost zero after treatment with the titanium peroxide gel of the present invention.

The process of the present invention, step (c) comprises regeneration of the gel for recycling and reuse. Accordingly, the titanium peroxide gel containing adsorbed contaminants obtained after filtration is washed with water followed by degradation of the contaminants. Degradation can be achieved by procedures selected from, but not limited to, exposure to natural or artificial light, physical treatment, chemical treatment, treatment with oxidizing agents such as hypochlorite or commercial bleaching agents and the like.

The regenerated gel can then be recycled and reused without much change in its effectiveness for the removal of the organic chromophore / dye / contaminant as discussed in step (a).

In addition, the titanium peroxide gel used in the process of the present invention can be synthesized from titanium alkoxide and hydrogen peroxide as precursors. Accordingly, titanium butoxide is hydrolyzed using deionized water to form precipitated titanium hydroxide followed by the addition of hydrogen peroxide to produce yellow colored titanium peroxide sol which in additional dilution provides very low viscosity titanium peroxide of 4x10- 3-5x10-3 Pa.s (4-5 cp). With maintenance for approximately 48 hours, polymer-free titanium peroxide gel is obtained with high viscosity in the range of 12-16 Pa.s (12,000-16,000 cps) and high zeta potential in the range of -54 to -25 mV. The concentration of titanium salt in the gel is in the range of 0.001-0.005% by weight.

The chromophores of the present invention are selected from, but not limited to, industrial effluents, organic chromophores, colored compounds, dyes, azo dyes and the like. The dyes are selected from the group of: methylene blue, methyl orange, basic violet, parabase, bromophenol blue and natural ink. Organic pollutants are selected from, but not limited to, hexamine, wastewater, methanol and phenol.

The solvents used to form a dye solution are selected from, but not limited to, water, acetone, chlorinated solvents, alcohols and the like.

Titanium (IV) radical complexes have strong absorption bands in the region of 300-500 nm and therefore induce photocatalytic process that accelerates the degradation of chromophores and organic pollutants adsorbed on the gel.

In the present invention, the photocatalytic activity of peroxide can be further improved by doping metals or metal oxides in the gel. Metals are selected from noble metals such as Au, Ag, Ni, Cu, Pt, etc. Metals such as iron, molybdenum, vanadium, tungsten as such or in salt form are also used as a doping agent. The particle size of the doped metals is less than 10 nm. The metals are doped in the range of 0.1-4% by weight.

In the present invention, doped with metals or metal oxides as described above reduces the energy of the band gap to allow the photocatalyst to exhibit photocatalytic activity even in the visible region.

The doped titanium peroxide gel is prepared by dissolving the aqueous solution of the metal precursors in the form of its salt or oxide in the solution of low viscosity titanium peroxide (4x10-3-5x10-3 Pa.s (4-5 cp)) and held for approximately 48 hours to obtain a polymer-free gel with high viscosity in the range of 12-15 Pa.s (12,000-15,000 cps) and high zeta potential in the range of -52 at -25 mV. Gel viscosity was measured using Brookfield viscometer with needle type RV. The zeta potential of the gels was measured using "90 Plus Particle size analyzer" by Brookhaven Instrument Corporation USA.

It is found that the process of the present invention is advantageous for the complete removal of chromophores / dyes together with the organic contaminants using said titanium peroxide gel optionally doped with metals or metal oxides as can be seen from zero absorbance in the visible range

The present invention is described in more detail with reference to the examples, which are provided by way of illustration only and therefore should not be construed to restrict the scope of the invention.

Example 1

The titanium peroxide gel used in the present invention was prepared using titanium butoxide (manufactured AR quality Aldrich) as a source of titanium. 4.6 g of titanium butoxide were hydrolyzed using 25 ml of distilled water resulting in the formation of titanium hydroxide precipitate. The titanium hydroxide supernatant was decanted and 25 ml of hydrogen peroxide (manufactured 50% Asian Peroxide) was slowly added to the titanium hydroxide. The highly vigorous and exothermic reaction between hydrogen peroxide with freshly prepared titanium hydroxide resulting in yellow colored titanium peroxide sol which was further diluted to

450 ml with distilled water to obtain titanium peroxide of very low viscosity of 5x10-3 Pa.s (5 cp). The titanium peroxide solution thus obtained was maintained for approximately 48 hours and the gel viscosity increased to 12 Pa.s (12,000 cps). The zeta potential of the gel thus obtained was measured and found to increase gradually to -54 millivolt indicating the stability of the gel. The gel with 12 Pa.s (12,000 cps) of viscosity and zeta potential of -54 millivolt was used in the present invention.

Example 2

The low viscosity titanium peroxide solution (5x10-3 Pa.s (5 cp)) was prepared as per the procedure given in example-1. A solution of nanoparticles was prepared by dissolving 0.021 g of chlorouric acid in 200 ml of distilled water and was further reduced using sodium borohydride solution (0.0045 g in 25 ml of water) to obtain pink colored solution. This pink gold nanoparticle solution was added to the aforementioned titanium peroxide solution to obtain a homogeneous violet colored transparent solution. The titanium peroxide solution containing gold thus obtained was stored for approximately 48 hours and the gel viscosity increased to 12-15 Pa-s (12,000-15,000 cps). The zeta potential of the gel thus obtained gradually increased to -31 millivolt which indicates increased gel stability over time. The gel with 15 Pa.s (15,000 cps) of viscosity and zeta potential of -31 millivolt was used in the present invention.

Example 3

The low viscosity titanium peroxide solution (5x10-3 Pa.s (5 cp)) was prepared as per the procedure given in example-1. Aqueous iron nitrate solution (0.055 g in 25 ml of water) was added to the aforementioned titanium peroxide solution. The titanium peroxide solution containing iron thus obtained was stored for approximately 48 hours and the gel viscosity increased to 12-15 Pa.s (12,000-15,000 cps). The zeta potential of the gel thus obtained was measured and found to increase gradually to -25 millivolt indicating the gel stability. The gel with 15 Pa.s (15,000 cps) of viscosity and zeta potential of -25 millivolt was used in the present invention.

Example 4

The low viscosity titanium peroxide solution (5x10-3 Pa.s (5 cp)) was prepared as per the procedure given in example-1. Vanadium pentoxide (0.05 g) was suspended in 25 ml of water. To this suspension, 5 ml of hydrogen peroxide (manufactured 50% Asian Peroxide) was slowly added to achieve a solution of peroxovanic acid colored light red. This peroxovanadic acid solution was added to the aforementioned titanium peroxide solution. The titanium peroxide solution containing vanadium thus obtained was stored for approximately 48 hours and the gel viscosity increased to 12-15 Pa.s (12,000

15,000 cps). The zeta potential of the gel thus obtained was measured and found to increase gradually to -27 millivolt indicating the gel stability. The gel with 15 Pa.s (15,000 cps) of viscosity and zeta potential of -27 millivolt was used in the present invention.

Example 5

The low viscosity titanium peroxide solution (5x10-3 Pa.s (5 cp)) was prepared as per the procedure given in example-1. Ammonium heptamolybdate (0.023 g) was suspended in 10 ml of water. To this suspension 5 ml of hydrogen peroxide (manufactured 50% Asian Peroxide) was slowly added to achieve a light yellow colored solution. This yellow solution was added to the aforementioned titanium peroxide solution. The titanium peroxide solution containing molybdenum thus obtained was stored for approximately 48 hours and the gel viscosity increased to 12-15 Pa.s (12,000-15,000 cps). The zeta potential of the gel thus obtained was measured and found to increase gradually to -57 millivolt indicating the gel stability. The gel with 15 Pa.s (15,000 cps) of viscosity and zeta potential of -57 millivolt was used in the present invention.

Example 6

The low viscosity titanium peroxide solution (5x10-3 Pa.s (5 cp)) was prepared as per the procedure given in example-1. Solution of Pt nanoparticles was prepared by dissolving 0.027 g of chloroplatinic acid in 200 ml of distilled water and further reduced using sodium borohydride solution (0.0045 g in 25 ml of water) to obtain pink colored solution. The black platinum nanoparticle solution was added to the aforementioned titanium peroxide solution to obtain a homogeneous dark colored transparent solution. The titanium peroxide solution containing platinum thus obtained was stored for approximately 48 hours and the gel viscosity increased to 12-15 Pa.s (12,000-15,000 cps). The gel with 15 Pa.s

(15,000 cps) viscosity was used in the present invention.

The titanium peroxide gel prepared as per example I is used in examples 7-8

Example 7

10 g of titanium peroxide gel was added to a 250 ml beaker containing 100 ml of 10-4 molar methylene blue solution. The solution was stirred vigorously and allowed to stand for five

minutes The blue methylene dye was adsorbed on the titanium peroxide gel and settled on the bottom of the beaker, the supernatant solution becoming colorless. The titanium peroxide gel containing the solution with adsorbed methylene blue dye was filtered using Whatman G1 filter paper to obtain colorless solution. The methylene blue content in the solution before and after the treatment was monitored by UV-VIS spectrophotometer (Shimadzu 2010) measuring its absorption at wavelengths 665, 612, 290 and 245 nm.

The optical absorption of the initial and final solution was as follows:

Wavelength

optical absorption Optical Absorption

(Initial)

(Final)

665 nm

6.0 0

612 mm

5.0 0

290 nm

3.34 0

245 nm

1.70 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of methylene blue from the aqueous solution.

Example 8

The filtered titanium peroxide gel using Whatman G1 filter paper containing methylene blue adsorbed in Example 7 above was transferred to a 250 ml beaker containing 10 ml of water. This beaker was kept in sunlight for 4 h until the blue color of the gel disappeared and its original yellow color was again achieved. Again 100 ml of 10-4 molar methylene blue solution was added to this regenerated gel, stirred vigorously and allowed to stand for five minutes. The methylene blue dye was adsorbed on the regenerated titanium peroxide gel and settled on the bottom of the beaker, the supernatant solution becoming colorless. The solution containing regenerated titanium peroxide gel with adsorbed methylene blue dye was filtered using Whatman G1 filter paper to obtain colorless solution. The methylene blue content in the solution before and after the treatment was monitored by UV-VIS spectrophotometer (Shimadzu 2010) measuring its absorption at wavelengths 665, 612, 290 and 245 nm. The optical absorption of the initial and final solution was as follows:

Wavelength optical absorption Optical Absorption

(Last initial)

665 nm 6.0 0

612 mm 5.0 0

290 nm 3.34 0

245 nm 1.70 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of methylene blue from the aqueous solution.

Example 9

The filtered titanium peroxide gel using Whatman G1 filter paper containing methylene blue adsorbed in Example 7 above was transferred to a 250 ml beaker containing 10 ml of water. To this gel was added 0.5 ml of 30% hydrogen peroxide. This beaker was kept in sunlight for 1.5 h until the blue color of the gel disappeared and its original yellow color was achieved again. Again 100 ml of 10-4 molar methylene blue solution was added to this regenerated gel, stirred vigorously and allowed to stand for five minutes. The blue methylene dye was adsorbed on the regenerated titanium peroxide gel and settled on the bottom of the beaker, the supernatant solution becoming colorless. The solution containing regenerated titanium peroxide gel with adsorbed methylene blue dye was filtered using Whatman G1 filter paper to obtain colorless solution. The methylene blue content in the solution before and after the treatment was monitored by UV-VIS spectrophotometer (Shimadzu 2010) measuring its absorption at the wavelengths of 665, 612, 290 and 245 nm. The optical absorption of the initial and final solution was as follows:

Wavelength

optical absorption Optical Absorption

(Initial)

(Final)

665 nm

6.0 0

612 mm

5.0 0

290 nm

3.34 0

245 nm

1.70 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of methylene blue from the aqueous solution.

Example 10

10 g of titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 250 ml of 10-4 molar solution of methylene blue was passed through this gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the gel and a colorless, clear solution was obtained as a filtered liquid. The methylene blue content in the solution before and after the treatment solution was monitored by UV-VIS spectrophotometer (Shimadzu 2010) measuring its absorption at the wavelengths of 665, 612, 290 and 245 nm. The optical absorption of the initial and final solution was as follows:

Wavelength optical absorption Optical Absorption

(Last initial)

665 nm 6.0 0

612 mm 5.0 0

290 nm 3.34 0

245 nm 1.70 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of methylene blue from the aqueous solution.

Example 11

10 g of titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 250 ml of 10-4 molar solution of methyl orange were passed through this gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the gel and a colorless, clear solution was obtained as a filtered liquid. The methyl orange content in the initial and final treated solution was monitored using UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at wavelength 464 and 270 nm.

The optical absorption of the initial and final solution was as follows.

Wavelength optical absorption Optical Absorption

(Last initial)

464 nm 2.5 0

270 mm 0.98 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of methyl orange from the aqueous solution.

Example 12

10 g of titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 250 ml of 10-4 molar solution of methyl violet was passed through this gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the gel and a colorless, clear solution was obtained as a filtered liquid. The content of methyl violet in the initial and final treated solution was monitored using UV-VIS spectrometer (Shimadzu 2010)

measuring its absorption at wavelengths of 581, 299, 246 and 205 nm. The optical absorption of the initial and final solution was as follows. Wavelength optical absorption Optical Absorption

(Initial) (Final) 581 nm 2.5 0 299 mm 0.7 0 246 nm 0.6 0 205 nm 1.5 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of methyl violet from the aqueous solution.

5 Example 13 10 g of titanium peroxide gel were taken on a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 250 ml of 10-4 molar malachite green solution was passed through this gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the gel and a colorless, clear solution was obtained as a filtered liquid. The content

10 in malachite green in the initial and final treated solution was monitored using UV-VIS spectrophotometer (Shimadzu 2010) measuring its absorption at wavelengths of 618, 423, 315 and 254.8 nm. The optical absorption of the initial and final solution was as follows. Wavelength optical absorption Optical Absorption (Initial) (Final) 618 nm 1.1 0 423 mm 0.2 0 315 nm 0.3 0

254.8 nm 0.6 0 Zero absorbance after treatment with titanium peroxide gel indicates complete removal of malachite green from the aqueous solution.

Example 14 10 g of titanium peroxide gel were taken on a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 250 ml of 10-4 molar solution of Rhodamine B was passed through this gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the gel and a colorless, clear solution was obtained as a filtered liquid. The content

20 in Rhodamine B in the initial and final treated solution was monitored using UV-VIS spectrophotometer (Shimadzu 2010) measuring its absorption at the wavelength of 551, 354 and 258 nm. The optical absorption of the initial and final solution was as follows.

Wavelength optical absorption Optical Absorption

(Initial) (Final) 551 nm 3.4 0 354 mm 0.3 0 258 nm 1.1 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of Rhodamine B from the aqueous solution. 25

Example 15

The gel used in example 11 above was regenerated using oxidizing sodium hypochlorite. 1 ml of commercially available 4% NaOCl solution was diluted to 100 ml. This diluted solution was passed through the gel used in the column. The adsorbed dye on the gel was completely degraded leaving the original yellow color of the gel. This gel was washed with an additional 200 ml of water to remove excess oxidant in the gel before it was reused. 250 ml of 10-4 molar solution of Rhodamine B was passed through this regenerated gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the regenerated gel and a colorless, clear solution was obtained as a filtered liquid. The rhodamine B content in the initial and final treated solution was monitored using UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 551, 354 and 258 nm.

The optical absorption of the initial and final solution was as follows.

Wavelength optical absorption Optical Absorption

(Initial)

(Final)

551 nm

3.4 0

354 mm

0.3 0

258 nm

1.1 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of Rhodamine B from the aqueous solution.

Example 16

10 g of titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 250 ml of 10-4 molar solution of bromophenol blue was passed through this gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the gel and a colorless, clear solution was obtained as a filtered liquid. The bromophenol blue content in the initial and final treated solution was monitored using UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 590, 434, 311, 261 and 214 nm.

The optical absorption of the initial and final solution was as follows.

Wavelength optical absorption Optical Absorption

(Last initial)

590 nm 3.3 0

434 mm 2.7 0

311 nm 1.2 0

261 nm 1.5 0

214 nm 4.0 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of bromophenol blue from the aqueous solution.

Example 17

10 g of titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 250 ml of 10-4 molar parabase solution was passed in a mixture of ethanol and water (5 ml of ethanol + 245 ml of water) at neutral pH (7) through this gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the gel and a colorless, clear solution was obtained as the filtered liquid. The parabase content in the initial and final treated solution was monitored using UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 540, 284 and 242 nm. The change in optical absorption was as follows:

Wavelength optical absorption Optical Absorption

(Initial)

(Final)

540 nm

0.5 0

284 mm

0.3 0

242 nm

0.65 0

Zero absorbance after treatment with titanium peroxide gel indicates complete removal of parabase from the aqueous solution.

Example 18

10 g of titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 250 ml of 10-4 molar solution of basic magenta was passed through this gel at a rate of 5 ml / min. The colored organic dye molecules were filtered through the gel and a colorless, clear solution was obtained as a filtered liquid. The basic magenta content in the initial and final treated solution was monitored using UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 542, 287 and 207 nm. The change in optical absorption was as follows:

Wavelength optical absorption Optical Absorption

(Last initial)

542 nm 3.7 0

287 mm 1.2 0

207 nm 2.9 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of basic magenta from the aqueous solution.

Example 19

10 g of titanium peroxide gel were taken in a 100 ml beaker containing 10 ml of ink solution. The solution was stirred vigorously and allowed to stand for about five minutes. The ink was adsorbed on the titanium peroxide gel and settled on the bottom of the beaker with the colorless supernatant solution. The solution containing titanium peroxide gel with adsorbed ink was filtered using Whatman G1 filter paper to obtain colorless solution.

Example 20

10 g of titanium peroxide gel were taken in a 250 ml beaker containing 100 ml of 10-4 molar solution of malachite green. The solution was stirred vigorously and allowed to stand for five minutes. The malachite green dye was adsorbed on the titanium peroxide gel and settled on the bottom of the beaker with the colorless supernatant solution. The solution containing titanium peroxide gel with adsorbed malachite green dye was filtered using Whatman G 1 filter paper to obtain colorless solution. The gel with adsorbed malachite green was transferred to a beaker and 100 ml of distilled water was added. The gel was exposed to sunlight for four hours and the gel returned to its original color. The gel was reused for the treatment of 10-4 molar solution of malachite green. The malachite green content in the initial and final treated solution was monitored using UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 618, 423, 315 and 254.8 nm.

The optical absorption of the initial and final solution after treatment with regenerated titanium peroxide gel was as follows:

Wavelength optical absorption Optical Absorption

(Last initial)

618 nm 1.1 0

423 mm

0.2 0

(continuation)

Wavelength optical absorption

Optical Absorption

(Initial)

(Final)

315 nm

0.3 0

254.8 nm

0.6 0

Example 21

10 g of gold and titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 100 ml of 564 ppm aqueous solution of formaldehyde was passed through the gel at the rate of 5 ml / min. The filtrate obtained contained 60 ppm of formaldehyde confirming 90% removal of formaldehyde from aqueous solution.

Example 22

10 g of gold and titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 50 ml of synthetic hexamine wastewater containing 1,000 ppm of formalin, 3,500 ppm of methanol, 2,000 ppm of hexamine and 500 ppm of ammonia in water were passed through the gel over a period of 3 h. The COD of the filtered liquid was 800 compared to the COD of 12,000 of initial hexamine wastewater before gel treatment.

Example 23

10 g of gold and titanium peroxide gel were taken in a 15 mm d glass column. i. and 25 cm in length provided with sintered disc (G0) and step valve to control the flow of the solution. 100 ml of 50% aqueous methanol solution was passed through the gel over a period of 2 h. The methanol content in the filtered liquid was monitored by UV-VIS spectrophotometer (Shimadzu 2010) measuring its absorption at the wavelength of 245 and 235 nm and comparison with the UV calibration curve. The methanol concentration decreased from 50% to 12.5%.

Example 24

10 g of titanium gold peroxide gel was added to a 250 ml beaker containing 50 ml of 500 ppm solution of phenol in water. The solution was stirred vigorously and allowed to stand for thirty minutes. The solution containing gold and titanium peroxide gel was filtered using Whatman G 1 filter paper. The COD of the filtered liquid decreased to 240 from 1,040 for initial 500 ppm phenol dissolution.

Example 25

10 g of titanium peroxide gel was added to a 250 ml beaker containing 100 ml of 10-4 molar solution of malachite green in acetone. The solution was stirred vigorously and allowed to stand for thirty minutes. The malachite green dye was adsorbed on the titanium peroxide gel and settled on the bottom of the beaker, the supernatant solution becoming almost colorless. The solution containing titanium peroxide gel with adsorbed malachite green dye was filtered using Whatman G1 filter paper to obtain almost colorless solution. The malachite green content in the solution before and after the treatment was monitored by UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 623, 427 and 341 nm with acetone as a reference. The optical absorption of the initial and final solution was as follows:

Wavelength optical absorption Optical Absorption

(Last initial)

623 nm 4.74 0.89

427 mm 3.97 0.87

341 nm 0.82 0.18

The considerable decrease in absorbance after treatment with titanium peroxide gel indicates the maximum removal of malachite green from the acetone solution.

Example 26

10 g of titanium peroxide gel was added to a 250 ml beaker containing 100 ml of 10-4 molar solution of malachite green in chloroform. The solution was stirred vigorously and allowed to stand for thirty minutes. The malachite green dye was adsorbed on the titanium peroxide gel with the gel floating in chloroform becoming the almost colorless chloroform layer. The solution containing titanium peroxide gel with adsorbed malachite green dye was filtered using Whatman G 1 filter paper to obtain almost colorless solution. The malachite green content in the solution before and after the treatment was monitored by UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 623, 427 and 341 nm with chloroform as a reference. The optical absorption of the initial and final solution was as follows:

Wavelength optical absorption Optical Absorption

(Initial)

(Final)

623 nm

> 5 0.81

427 mm

> 5 0.83

341 nm

1.96 0.33

The considerable decrease in absorbance after treatment with titanium peroxide gel indicates the maximum removal of malachite green from the chloroform solution.

Example 27

10 g of titanium peroxide gel was added to a 250 ml beaker containing 100 ml of 10-4 molar solution of methyl violet in acetone. The solution was stirred vigorously and allowed to stand for thirty minutes. The violet methyl dye was adsorbed on the titanium peroxide gel and settled on the bottom of the beaker, becoming the almost colorless supernatant solution. The solution containing titanium peroxide gel with adsorbed methyl violet dye was filtered using Whatman G1 filter paper to obtain almost colorless solution. The content of methyl violet in the solution before and after the treatment was monitored by UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 581 and 543 nm with acetone as a reference. The optical absorption of the initial and final solution was as follows:

Wavelength optical absorption Optical Absorption

(Last initial)

581 nm 1.35 0.32

543 mm 1.03 0.25

The considerable decrease in absorbance after treatment with titanium peroxide gel indicates the maximum removal of methyl violet from the acetone solution.

Example 28

10 g of titanium peroxide gel was added to a 250 ml beaker containing 100 ml of 10-4 molar solution of methyl violet in ethanol. The solution was stirred vigorously and allowed to stand for thirty minutes. The violet methyl dye was adsorbed on the titanium peroxide gel and settled on the bottom of the beaker, becoming the almost colorless supernatant solution. The solution containing titanium peroxide gel with adsorbed methyl violet dye was filtered using Whatman G1 filter paper to obtain almost colorless solution. The content of methyl violet in the solution before and after the treatment was monitored by UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the wavelength of 581 and 543 nm with ethanol as a reference. The optical absorption of the initial and final solution was as follows:

Wavelength optical absorption Optical Absorption

(Last initial)

581 nm 3.89 0.29

543 mm 3.22 0.23

The considerable decrease in absorbance after treatment with titanium peroxide gel indicates the maximum removal of methyl violet from the acetone solution.

Example 29

10 g of gels prepared as per the procedure given in Examples 2-6 were added separately to 250 ml beakers containing 100 ml of 10-4 molar solution of methylene blue. The solutions were vigorously stirred and allowed to stand for five minutes. The blue methylene dye was adsorbed on these gels and settled on the bottom of the beakers, the supernatant solution becoming colorless. The solution containing gels with adsorbed methylene blue dye was filtered using Whatman G1 filter paper to obtain colorless solution. The content of methylene blue in the solution before and after treatment was monitored by UV-VIS spectrophotometer (Shimadzu 2010) by measuring its absorption at the length of

10 wave of 665, 612, 290 and 245 nm. The optical absorption of the initial and final solution for all gels was the same and was as follows:

Wavelength optical absorption Optical Absorption

(Last initial)

665 nm 6.0 0

612 mm 5.0 0

290 nm 3.34 0

245 nm 1.70 0

Zero absorbance after treatment with titanium peroxide gel indicates the complete removal of methylene blue from the aqueous solution.

Gels filtered using Whatman G1 filter paper containing adsorbed methylene blue was transferred to the vessel

15 250 ml precipitates containing 10 ml of water. These beakers were kept in sunlight until the blue color of the gel disappeared and again its original color recovered. The activity of the gels for degradation of methylene blue in sunlight was in the following order:

Pt-Ti gel (example 6)> Au-Ti gel (example 2)> Mo-Ti gel (example 5)> V-Ti gel (example 4)> Fe-Ti gel (example 3)> Ti gel (example 1 )

Claims (9)

1. A one-step process for the removal of organic dye and / or organic solution contaminants using titanium peroxide gel, said process comprising: a) add titanium peroxide gel to the solution in a ratio ranging from 1: 5 to 1:20 volume / volume of gel / dye solution; b) stir the mixture as obtained in step (a) vigorously at a temperature ranging from 25-35 ° C; c) Let the mixture stand as obtained in step (b) for 5 to 25 minutes to obtain an organic dye or contaminant adsorbed on a titanium peroxide gel and a colorless supernatant, of course, followed by filtration of the mixture to obtain dye or contaminant. organic adsorbed on titanium peroxide gel; d) transfer organic dye or contaminant adsorbed on titanium peroxide gel as obtained in the step (c) in a beaker containing water; e) degrade dye or organic contaminant adsorbed from the dye or organic contaminant adsorbed on titanium peroxide gel to recover the titanium peroxide gel for reuse.

2.

The process according to claim 1, wherein the solution used in step (a) comprises organic dye and / or organic contaminants and a solvent selected from the group consisting of: water, acetone, chlorinated solvents and alcohols.

3.

The process according to claim 1, wherein the titanium peroxide gel used in step (a) has a zeta potential in the range of -54 to -25 mV and viscosity in the range of 12-15 Pa.s ( 12,000-15,000 cps).

Four.

The process according to claim 1, wherein the titanium peroxide gel used in step (a) is optionally doped with noble and transition metals selected from the group consisting of: Au, Ag, nickel, copper, iron, molybdenum , vanadium, tungsten and platinum in the range of 0.1-4% by weight.

5.

 The process according to claim 1, wherein an organic dye or an organic contaminant is selected from the group of: methylene blue, methyl orange, methyl violet, malachite green, Rhodamine B, bromophenol blue, parabase solution, solution of magenta, ink, formaldehyde solution, synthetic hexamine wastewater, phenol.

6.

The process according to claim 1, wherein the titanium peroxide gel used in step (a) is optionally placed on a column and the dye solution is passed through it to obtain clear, colorless supernatant.

7.

The process according to claim 1, wherein the concentration of the organic dye and organic contaminants is removed up to 95-100%.

8.

The process according to claim 1, wherein said degradation of organic dye and organic pollutant of organic dye or contaminant adsorbed on titanium peroxide gel in step (e) is done by exposing it to sunlight with or without an oxidant.

9.

The process according to claim 8, wherein the oxidant used is selected from the group consisting of hydrogen peroxide and sodium hypochlorite.